This invention provides a two-step enzymatic process for the synthesis of monoprotected diols from symmetric diols.
Selective protection of diols having the general formula HO—(CH2)n—OH remains a challenge. Frequently, treatment of these diols with a stoechiometric amount of a reagent aimed at forming a derivative of the hydroxy functionality results in the formation of a 1/2/1 mixture of unreacted diol, the monoprotected and the bis-protected derivative respectively. Houille, Olivier et al., A Remarkably Simple Process for Monoprotecting Diols, Tetrahedron Letters, Vol. 37, No. 5, 1996, pp. 625–628.
Chemical synthesis of a monoprotected diol from a symmetric diol employing routing acetylation procedures has proven to be unfeasible due to poor selectivity and low yield with poor reproducibility. The procedure presented in the O. Houille paper (Id.) proved to be unpractical due to the lack of commercial availability of starting material and use of lipase (PPL) produced from animal sources. Our procedure of this invention employs two commercially available lipases from microorganisms.
This convenient process can be utilized to synthesize other monoprotected diols from symmetric diols.